Detection of murine post-pneumonectomy lung regeneration by 18FDG PET imaging

To determine if murine lung regeneration could be detected in vivo, we studied inbred mice 3, 7, 14, and 21？days after left pneumonectomy. The remaining lung was imaged using microCT as well as the glucose tracer 2-deoxy-2-[18？F]fluoro-d-glucose (18FDG) and positron-emission tomography (PET). Because of the compliance of the murine chest wall, reproducible imaging required orotracheal intubation and pressure-controlled ventilation during scanning.After left pneumonectomy, the right lung progressively enlarged over the first 3？weeks. The cardiac lobe demonstrated the greatest percentage increase in size. Dry weights of the individual lobes largely mirrored the increase in lung volume. PET/CT imaging was used to identify enhanced metabolic activity within the individual lobes. In the cardiac lobe, 18FDG uptake was significantly increased in the day 14 cardiac lobe relative to preoperative values (p？<？.05). In contrast, the 18FDG uptake in the other three lobes was not statistically significant at any time point.We conclude that the cardiac lobe is the dominant contributor to compensatory growth after murine pneumonectomy. Further, PET/CT scanning can detect both the volumetric increase and the metabolic changes associated with the regenerative growth in the murine cardiac lobe.The capacity for adult tissue regeneration has heightened interest in the longitudinal and minimally invasive visualization of these complex biologic processes [1]. Molecular imaging of dynamic processes such as tissue regeneration provides an opportunity not only to characterize the biologic process at the cellular and molecular level but also to measure the impact of therapeutic interventions [2-4].The dominant clinical and experimental approach to characterizing biologic processes has utilized the glucose analogue tracer 2-deoxy-2-[18？F]fluoro-d-glucose (18FDG) and positron-emission tomography (PET). FDG-PET can discriminate between tissues with normal and increased glucose metabolism. Recent